[bombcar]

3.5x10⁵ km³ you say?

1.08321×10¹² km³ is the volume of Earth, feasibility study done! Implement!

[hermitcrab]

The molten core probably isn't going to be much use.

Surface area is 5x10^8 km^2. So it it 'only' the first ~2m of the crust (~6m if you don't count ocean).